The effects of promoters of chemical carcinogenesis on the cell mediated immune response system will be investigated. Preliminary indications show that in vivo promoter treatment with 12-0-tetradecanoylphorbol-13-acetate (TPA) can either increase or decrease the immune response potential depending on the method of treatment with promoter. These results will be extended to include characterization of the doses and kinetics of promoter treatment for immune response modulation. The ability of various tumor promoters and non-promoting phorbol esters to modulate the immune system will be tested and competitive interactions between these compounds and TPA will be measured. The stage(s) in the development of an immune response which can be affected by promoter will be determined. Immune response modulation by long term promoter treatment will be studied as will the ability of promoter to alter the growth pattern of antigenic tumors. Cellular effects of TPA on lymphocytes will be studied including alterations in blastogenesis, membrane fluidity, protein synthesis, and cyclic nucleotide levels.